Has sizing felt different to anyone else?

I’ve been buying killstar for about 4 years now and my body hasn’t changed much (5”7 145lbs) and I genuinely can’t fit into certain things anymore. I don’t usually get pants but I recently ordered the velour bell bottoms in a medium which ended up being too small (the last medium pants fit like a glove) and tops seem to be hit and miss, most mediums are too snug and larges hang off of me. I think it may vary by style but my partner has the same issue despite being smaller than me (her weight tends to fluctuate more than mine though.) the only things that seem to stay consistent are dresses. Also why aren’t plus sized tights a thing? I’ve destroyed about three pairs of libra tights first wear, where’s the love for bigger girls or at least those of us who are shaped like mewtwo?

Anyway I’m not looking for criticism, I’m just wondering if anyone else has experienced this. I’m still gonna keep buying their stuff and have anxiety when picking sizes.