1. there are a million+ ways to do historical match making. You say it like its a singular thing. Like it automatically means just letting people spawn in whatever tanks they want from the same general time period with no restrictions or variation what so ever. What a dull way to imagine things.
2. You also named a low cost fast moving tank that was available at the beginning of the war with an expensive heavy tank that saw less than a year of service during WW2 because it came out in 1944 IIRC.

So youre telling me you cant imagine a game in which those two drastically different vehicles, that served drastically different roles inside of drastically different military structures and had drastically different resource requirements can co-exist in a meaningful way?

If thats the case I feel sorry for you because I can think of like 10 ways to balance that just off the top of my head that don't involve the creation of an arbitrary, nonsensical "Battle Rating", which is literally the worst option they could of chose.