Advice on varnishing oils

In my time, I've used many different varnishes, some a lot more satisfactory than others.  Years and years ago, I used dammar varnish - which yellows, darkens, and can only be removed with real Turpentine, ordinary mineral spirits won't touch it.  There are many others now.  Anyway: I thought, given I've had trouble with varnishing and suspect I'm not alone, that this link would be useful, from Natural Pigments - they know their stuff. https://www.naturalpigments.com/artist-materials/varnishing-paintings-techniques-tips?utm_source=youtube&utm_medium=video&utm_campaign=varnish The link's not live, but you can highlight it and right click on it (on a pc at least) and it'll give you the go-to option.