IMO you are overthinking it.
There are two schools of thought.
One -- e.g. elanjacobs -- says don't buy a router that can't take 1/2" bits.
the other says at the outset plan on eventually buying three routers -- start with a router designed to work with 1/4 and 8 mm shank bits, then add either a trimmer (for edge profiling and similar) or a large router designed for large 1/2" shank bits (plan on mounting the large router in a table). Add the 3rd router as you refine you uses.
Both schools of thought are valid.
What I will add is that this will be your first router. I have well over $4,000 worth of a router bits -- mostly inherited from my father -- thanks dad.
A lot of them are 1/4" shank bits, a smaller number are 8 mm shank ones, plus 1/2" inch ones.
the 1/4" shank ones are mostly for detail work. The smallest is a 1/16" straight cutter and the largest (1/4" shank) is 19mm across the profile. I only rarely use this one. Many of my 1/4" shank bits are for routing edge profiles.
The 8 mm shank bits are heavier (shank wise) than the 1/4" bits and are intended for use with the Leigh and Gifkins dovetail and box joint jigs.
The 1/2" bits vary from a 3/8" solid carbide up-cut spiral, through morticing bits, finger joint cutters, and rail and style bits, plus a very large (89mm dia) panel raising bit.
My thoughts are that a router capable of taking an 8mm collet will have sufficient power for your likely use.
8 mm shank bits should be "strong enough" for any profile smaller than about 30 mm dia. Note that now Lee Valley stock Festool routers, 8mm shank bits are readily available in North America.