you need a lead paint encapsulant https://www.homedepot.com/p/ECOBOND-LBP-1-gal-Lead-Defender-PRO-Off-White-Flat-Interior-Exterior-Paint-and-Primer-Lead-Paint-Sealant-and-Treatment-ECO-LBP-1001-P/202830398

this is the family room and the other side of the see thru fireplace. I also included a pic of the outside of the house which has the same brick as the fireplace. I'll paint the outside too (eventually)

We are stripping old paint from our wooden mantle. We started with Citristrip, which worked OK but not great. Washed it with mineral spirits and then applied Klean Strip paint remover, which worked much better. We didn’t finish completely so we cleaned the area and covered the mantle with a plastic tarp. When we walked into the house today after being out all day, the house smelled like sewage or rotten food (not exactly like sulfur). I thought that the methanol and ethanol in the Klean Strip could have decomposed somehow and left the smell. Has anyone else experienced this?

How I'd remove 1 layer of paint is I'd call a pro and let them do it. It's 2021 and I don't know anyone who uses regular paint on brick - interior or exterior. Instead of the schmear, consider a mineral paint like Romabio.A lot easier and their Instagram account is inspirational and lots of good tips about proper application.