IMO, your initial posts seem to indicate you still like your 7DI. Yes, newer bodies have better specs, but if you haven't found a limitation, then there's no point in upgrading (one of the important aspects of not getting into GAS). With my route, my first DSLR was a 5DI because it was a new FF I could afford. Even though the 5D2 had higher MP and video capabilities, I never felt compelled to buy it because it had the same AF (the main feature I found lacking with the 5D: even coming from previous MF SLRs). I upgraded to the 5D3 because of its way much improved AF, and found that its DR was better (no longer got noise with even the most conservative shadow raise). For stills, the 5D4 is a nice upgrade for me as well with higher MP and DR (the AF spread is just slightly wider then 5D3). I did own the 7D2 for a bit (but didn't use it much because I am a FF person). Its high ISO is still supposed to be competitive, but the huge advantage it has for crop models is AF and continuous speed.
Lenses, though, have a better shelf life and less depreciation in value. Canon 100-400 or Sigma 150-600 (C or S) are all great lenses to consider. I got the Sigma 150-600c because I just use the ultra-telephoto occasionally, and the c is easier to hand hold (read that optically, C and S are pretty equal).