I'm very much the same mate, infact i probably annoy most vendors nowadays as i'm always messaging asking whats the most gassy batch on the menu (the reason i ask them is you can't just rely on strain name and copy pasted descriptions for your terps, every batch is different pheno's etc)
but i've got some bad news for you, just done a quick calculation and i spend between £4500-5500 on here every year (i buy 7g's a week) and each and every purchase i'm chasing those gassy terps that you speak of, and if i'm VERY lucky, i will get maybe 5 bits of weed in a whole year that actually has real gassyness to it, so around £4000 a year is literally wasted down the drain for me on here even though i make sure to always pick the strains with the most potential for gassy terps, it's just a never ending cycle of being let down, lots of frustration and wasted money.
imo the main problem is false advertising, and since 'gassy' is now associated with anything grown in cali, people just use the word 'gassy' to generate hype and sales when 99.9999999999% of the time in my long term experience there's not a fucking hint of gas in sight! i've bought about 10 cali packs on here this year too in a desperate attempt to finally get some weed that is tasty and gassy and what a fucking surprise, all of it has been a let down / enormous waste of money lol
best of luck to you though mate on the hunt for the gas