Maybe the easiest thing to do is just go get some additional seatime on bigger working vessels.That’s not difficult to do in the current job market.
1.5 days of seatime (for 12 hour days) on tugs, OSVs , or FVs adds up quickly.
If sail time is specifically needed, there are places like SEA in Woods Hole.
I happened to notice an ad for crew the other day for a 500 GT Dutch sailing vessel doing seasonal voyages on the coast of Greenland.
Oceanwide (the Netherlands office) also has a 500 GT sailing vessel doing the same thing. I’ve seen their ads in the past.