Staining woodwork

I have a substantial amount of stained moldings/woodwork in my house, which is generally in pretty good shape. It needs to be touched up after the renovation here and there. I believe the wood is pine and it was stained by the previous owner, but not with shellac as I tried rubbing it with alcohol and it wasn’t coming off but rather became bubbly. I tried some minwax wood finish and after 5 days it is very sticky, as if I just painted it (seems like it’s not absorbing). I don’t want to sand the woodwork as it’s a lot of work, but want to give the wood a coat of something that would cover up all the small imperfections. Any idea which product to use? (it’s currently stained dark walnut)