2 routers connected to one ONT

[kfkfkf11]

I am moving and we will possibly be sharing the fibre with the neighbouring apartment.

I'm wanting to know if connecting a second router to the ONT compromises the speed more than an extender/repeater (or possibly 2) would. The signal from the one apartment is not strong enough to reach most of the other apartment. We would use a long ethernet cable to connect from the ONT to the router in our apartment. We are upgrading the RSAweb package from uncapped 10/5 to 20/20.

 

[Fcon_Vpro]

You would most likely only have 1 router connected to the ONT and then the second router connected to the first router. But 2nd router would have DHCP, etc disabled.
So 2nd router is more of an access point or switch, than a full on router.
Afaik you cant connect 2 routers to 1 ONT.