Since I can't use a smart switch for this light, I'm looking to use a smart bulb. However, I have a limitation in terms of bulb size. I'm currently using an A19 bulb with a T2 format. But I can't find an alternative that matches the bulb's dimensions. Do you have any ideas?
Are you not able to use a smart switch in general or just because you are using the Fluorescent Bulb? Options might be, smart switch with dimmable candelabra LED bulb with A19 adapter or smart Candelabra LEDs (sengled has some, but some people say they have issues with Sengled) with an A19 adapter. This is assuming the adapter won't make the bulbs too tall for your application.
If it is on the same breaker as the outlet right next to it, then you can use a pigtail from the outlet’s neutral. That will let you install a smart switch.