I’ve been traveling with The North Face’s Medium Rolling Thunder for the last 10 years where I go on one big international, multi-week and multi-airport (stopover) trip annually. Since 2014 it is now 2-3 big trips a year and in 2015 I got certified so that’s when dive vacations started. All my scuba gear goes in there 2-3 times a year now and we go faaaaar. Day and a half to get there far. This bag is basically their famous Base Camp Duffel but with wheels.

I fit everything in it - clothing, toiletries, BC, fins (Mares Avanti Quattro + so they are stiff and full sized), boots, 5mm full wetsuit plus 3/4/5 hooded vest OR my 8/7 semidry, backup mask, DSMB, and other essentials.
Check out their Refractor duffel clamshell backpack for carry on for your regulator, mask, etc. It’s amazing and has comfortable straps and room for laptop and other items. My go-to. More recently I started traveling with UW photo gear so my reg gets checked into the Rolling Thunder as well.
Both these bags have lifetime warranties including zippers and stitching. They have proven the test of time and are both made out of tarpaulin and are therefore water resistant. I will not use anything else - I love them so much. Mr. OOO also has the same Rolling Thunder and his is still going. I highly recommend. The handle is high quality as are the wheels. Smooth, easy to maneuver even on uneven terrain, and quiet.