Nothing takes the place of good sanding. Nothing. You're going to have to deal with the lead sooner or later. It might as well be sooner.

My sister has to use a heat gun to remove paint from siding before repainting. It took a lot of days to finish removing the old paint. If was cracking and pealing, mostly on the southern side but other areas too. I didn't ask her if she checked to see if any lead paint, could have been since house was built in the 1950's. There is no way that a filler would have leveled out the old paint.

And the only kind of heat to use on lead-containing paint is an infrared gun that won't cause it to get so hot that it poses a health risk by vaporizing the lead.

Maybe this would help?

Makita GV5010 5" Disc Sander is what we bought to sand down our front porch columns. It is a workhorse and made quick work of removing layers of paint. Lightweight, powerful, easy to control. Highly recommend.

...as long as lead isn't in the paint. Otherwise you are creating a serious contamination and risk situation and possibly violating local pollution regulations.