I found this fix on youtube, it sounds funny but has actually worked for multiple consoles.
“I fixed mine and it’s been stuck for a month. I basically did CPR on it. I blew along the edges and awkwardly put the entire L button in my mouth then did one big blow. Then inhaled after and it popped back up.”
I know it sounds ridiculous, but this technique worked on my switch lite after the R button had been stuck for months.