These will work or another brand that does the same thing.

https://www.amazon.com/Rextin-adapter-Pigtail-Ceiling-downlight/dp/B07J5411KB/ref=sr_1_5?dchild=1&keywords=light%2Bbulb%2Bwire%2Bsocket&qid=1587788244&sr=8-5&th=1

the lights are only about 3 inches deep so there is plenty of room for the box in there as well. And most can light housings are adjustable via a wing nut in there that you can loosen and push the inside up for the maximum room. They're adjustable so you can place the BR30 bulb in the optimal spot without worrying if one is 1/4 inch different than the one being replaced. But also helpful to give you more room.

Lol yeah I've been mulling it over myself. I think I may have come up with a solution....

The idea is to use a bulb with a pigtail: https://www.amazon.com/gp/product/B07J5411KB/ref=ewc_pr_img_3?smid=AWDHA2H8OE6J8&th=1

And add a grounded pigtail: https://www.amazon.com/gp/product/B00IOXG1X0/ref=ewc_pr_img_1?smid=A2FQL10UCAZUR8&psc=1

And connect those wires to this canless light with spring clips: https://www.amazon.com/Canless-Recessed-Gimbal-Downlight-Rotatable-Spotlight/dp/B099WYF93K?th=1

(For some reason the link sends you to a square trim... mine would be the 4" round)

I'm thinking it'll work! Not 100% sure yet, but my current thoughts