If both teams end on the same record do they check maps or round differential?
Yeah.
Similar case: GENG, currently 3-2 with +4 map diff. TS 3-3 with +0 map diff.
Regardless of GENG score tomorrow (losing 2-0, 2-1) they'll be the top seed for group Alpha because of their map diff.
https://www.vlr.gg/event/2002/champions-tour-2024-pacific-stage-1/regular-season