Well in this case that just doesn't work. TF2's current state is unstable and at some points plain broken. Updates trying to fix bugs just create more which shows how poorly the game's maintained, which is now completely understandable seeing how few people actually work on it. I also still don't understand why Valve isn't porting this game to Source 2. Hideous lag compensation model: gone. Crappy performance on powerful machines that have no issues with more modern titles: dealt with. Up-to-date toolset for content creators: check. DX11/DX12/Vulcan support for reduced driver overhead and more performance out of the mid-range computer systems: yes please. Thousands of little bugs that are there just because it's Source: gone. The benefits outweigh the drawbacks by a factor of about, lets say, 10 billion.

What do they do instead? Add a game mode that deviates so much from the main game it could be it's own separate game, make weapon balance changes only 5 year olds can think of (and then refusing to fix them like 4 months down the line (looking at you, Tide Turner)). And now this matchmaking system comes along which is already starting to look crappier and crappier the more information about it becomes available. Why even bother with it? Make a stable game first, then add content.

As for the invisible players: it happens because of a desync with the server, where the server sends a packet containing player information that never arrives or arrives corruptly. TF2's client never asks for a new one however, resulting in invisible players. Typing record s; stop in the console fixes this, as the record command first demands a complete up-to-date server state before recording a demo which results in the data packets being sent again.