I would like to suggest that the ORBAT displayed at the start of the match, where players select classes, remain on screen for 30 seconds while players choose their preferred class and spawn point without limitations being placed on choices, but clearly showing the numbers allowed and the numbers trying to select them.
If a class or spawn is oversubscribed at the end of the selection period then access to it is determined by an RNG roll. Failure to gain access to an oversub'd class slot returns the player to the normal ORBAT for respawning.
Because access to 'flavour of the month' class slots shouldn't be determined by latency and hardware investment.
Optionally, allow small weighting of the RNG access roll for players who have earned notable accolades in their chosen class.