There is no easy answer. In your shoes, I'd focus on the overall bike and consider which seems best suited to my needs and budget. I'd gladly take a small step down in component group if I could get better wheels, frame or even saddle for the same dollars.

Components today are all very good, and all groups benefit from trickle-down as the A-line stuff is improved every year or two. That's why, even though I'm in the industry, and distributed Campagnolo for a number of years, I've always ridden Chorus which I feel gives me 95% of the features of Record, at roughly 65% of cost.

In Shimano there seems to be some sort of artificial line with 105 being the lowest in the "racing" group and Tiagra at the top of the recreational groups, but that's more about marketing than technology. Whatever you decide, don't fall into the trap of buying with the intent of upgrading. That's the most expensive way to buy a bike, though I make an exception for saddles.

In my 45+ years riding and in the industry, I've never pulled off and upgraded a working component, though I often replace with better if one dies.