I use epifanes varnish for anything involving water. They have a version that doesn’t have UV blockers for indoor work so is doesn’t have the yellow cast most spar varnishes have.
Epiphanies has a very high solids ratio.
And it is renewable, unlike poly varnishes.
Christian Becksvoort shows how to use it as a wiping varnish mixing it 50-50 with tried and true linseed oil.
Works well on things like tables and desktops, also.
The downside is it’s a bit spendy, but worth it.