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What I would do is:

1. Apply for ESTA, specifying you're a US citizen. Some people on this site have reported it works.
2. If the ESTA is approved, you're good to go.
3. If the ESTA is rejected, buy a ticket to Canada (Vancouver or Toronto are a good bet) or Mexico (Tijuana), then take the bus, train or drive a rental car to the US. If you go to Tijuana you could also just walk across the border very easily thanks to the Cross Border bridge.
4. Since October 1st 2022 VWP-eligible passports are required to apply for ESTA in advance, so taking public transit might be a little more tricky, as some bus operators verify your documents in advance, though it's not clear if they now also check that you have a valid ESTA. So if you don't want to drive a rental car, your best bet would be to use an operator that doesn't check IDs, take the Amtrak from Vancouver (where there's CBP officers at the station) or go to Tijuana as mentioned above.

Once you're at the US border the CBP officer will pretty much have no choice but to let you in. As an absolute worst case scenario you'll have to wait a bit in secondary inspection while they verify your naturalization details.

You could of course go to the US consulate for an emergency passport but this might be more hassle than just flying in via Canada/Mexico.

Update: looks like OP reported that getting an emergency passport was super quick. Updating my answer accordingly.

What I would do is:

1. See how fast you can get an emergency passport. If it's quick enough, go get it. Otherwise...
2. Apply for ESTA, specifying you're a US citizen. Some people on this site have reported it works.
3. If the ESTA is approved, you're good to go.
4. If the ESTA is rejected, buy a ticket to Canada (Vancouver or Toronto are a good bet) or Mexico (Tijuana), then take the bus, train or drive a rental car to the US. If you go to Tijuana you could also just walk across the border very easily thanks to the Cross Border bridge.
5. Since October 1st 2022 VWP-eligible passports are required to apply for ESTA in advance, so taking public transit might be a little more tricky, as some bus operators verify your documents in advance, though it's not clear if they now also check that you have a valid ESTA. So if you don't want to drive a rental car, your best bet would be to use an operator that doesn't check IDs, take the Amtrak from Vancouver (where there's CBP officers at the station) or go to Tijuana as mentioned above.

Once you're at the US border the CBP officer will pretty much have no choice but to let you in. As an absolute worst case scenario you'll have to wait a bit in secondary inspection while they verify your naturalization details.

What I would do is:

1. Apply for ESTA, specifying you're a US citizen. Some people on this site have reported it works.
2. If the ESTA is approved, you're good to go.
3. If the ESTA is rejected, buy a ticket to Canada (Vancouver or Toronto are a good bet) or Mexico (Tijuana), then take the bus or drive a rental car to the US. Once you're at the US border the CBP officer will pretty much have no choice but to let you in. As an absolute worst case scenario you'll have to wait a bit in secondary inspection while they verify your naturalization details.

You could of course go to the US consulate for an emergency passport but this might be more hassle than just flying in via Canada/Mexico.

What I would do is:

1. Apply for ESTA, specifying you're a US citizen. Some people on this site have reported it works.
2. If the ESTA is approved, you're good to go.
3. If the ESTA is rejected, buy a ticket to Canada (Vancouver or Toronto are a good bet) or Mexico (Tijuana), then take the bus, train or drive a rental car to the US. If you go to Tijuana you could also just walk across the border very easily thanks to the Cross Border bridge.
4. Since October 1st 2022 VWP-eligible passports are required to apply for ESTA in advance, so taking public transit might be a little more tricky, as some bus operators verify your documents in advance, though it's not clear if they now also check that you have a valid ESTA. So if you don't want to drive a rental car, your best bet would be to use an operator that doesn't check IDs, take the Amtrak from Vancouver (where there's CBP officers at the station) or go to Tijuana as mentioned above.

Once you're at the US border the CBP officer will pretty much have no choice but to let you in. As an absolute worst case scenario you'll have to wait a bit in secondary inspection while they verify your naturalization details.

You could of course go to the US consulate for an emergency passport but this might be more hassle than just flying in via Canada/Mexico.

What I would do is:

1. Apply for ESTA, specifying you're a US citizen. Some people on this site have reported it works.
2. If the ESTA is approved, you're good to go.
3. If the ESTA is rejected, buy a ticket to Canada (Vancouver or Toronto are a good bet) or Mexico (Tijuana), then take the bus or drive a rental car to the US. Once you're at the US border the CBP officer will pretty much have no choice but to let you in. As an absolute worst case scenario you'll have to wait a bit in secondary inspection while they verify your naturalization details.

You could of course go to the US consulate for an emergency passport but this sounds might be more hassle than just flying in via Canada/Mexico.

What I would do is:

1. Apply for ESTA, specifying you're a US citizen. Some people on this site have reported it works.
2. If the ESTA is approved, you're good to go.
3. If the ESTA is rejected, buy a ticket to Canada (Vancouver or Toronto are a good bet) or Mexico (Tijuana), then take the bus or drive a rental car to the US. Once you're at the US border the CBP officer will pretty much have no choice but to let you in. As an absolute worst case scenario you'll have to wait a bit in secondary inspection while they verify your naturalization details.

You could of course go to the US consulate for an emergency passport but this might be more hassle than just flying in via Canada/Mexico.