I could go on together after working in a high end shop for around 6 years through high school and summers during college, but thankfully Redrum seems to have made the major points already.
I’ll just repeat it again…fit is the most important thing. Make SURE the person fitting you really knows what they’re doing since it means the difference from riding in a relaxed/comfortable position, and hating getting on the bike.
Be aware that different bike manufacturers tend to cater to different body types, so don’t get set on a brand before getting fit. Find out which brands fit you first and go from there. If it turns out you don’t fit any of the off the shelf options, and this does occasionaly happen, there’s always companies like Independent Fabrications (assuming they’re still around) that build custom frames at a reasonable price.
I remember going through frame dimensions on at least 20 brands before finding one that made a frame that fit me just right without correcting more than is prudent with seat position and stem length.
Ugh I really need to ride this year…
-Mike