Third person online shooter


I am working on a third person online shooter project. And i would kindly request feedback on my issue (and/or) best possible solution to make a online lobby + match playthrough, so that multiple players can join a match and start shooting each other on Steam servers. The match will be 2 different teams battling each other.

What i want feedback in: Which solutions are most cost effective and easiest to make? Because I will hire freelancers to help me create it. Other ideas or solutions are warm welcome.

I consider using the tool Uworks from the marketplace, i think it could be very helpful to use in order to integrate the game with steam online play.

I would like the game to have the same concept as Ring of Elysium? (ROG)

Here in the first picture, the player got to choose solo, duo or squad. Could be good for players who wants to play with friends.

The Second picture, in the next step players can choose where to spawn on the map at beginning until the time runs out and the match starts.

For my project:
Because of the two different teams, they will have their own side to spawn on. One team on the upper side and one team on the lower side. The player can’t spawn on the enemy spawn area because there is a line they can’t cross in the middle.
A player only has 1 life so once the player is dead it will be sent back to the main menu.
The team that have killed all the other players on the opposite team wins.

Is it possible to archive 100 players in one online match? The game assets for the game are low polly and highly opimiced alongside with the very big map which has the same sice as (ROG)

However, the more players the better.

I know it can be hard to tell the amount of hours/weeks necessary to create this but would be appreciated if someone (programmer/blueprint-specialist) could make a estimate of a fixed price and time of what it would require to manage this Steam Online multiplayer function.