Access Group Conditions: Select Opportunities of a branch where the user is a resource of

I need to display only the opportunities belonging to a branch the user is a part of. We made a custom object called "LinkBranchResource" which links custom Object Branch and Resource Object, so a Resource can be part of multiple branches. In access groups I want to create a rule such that the user must only be able to view the opportunities he's part of. We faced multiple challenges for this requirement:

1. DSP SQL Predicate is not supported in Redwood so we can't write SQL and limit the opportunities.
2. Access Groups: We have to manually create the object rule for each and every condition. There are around 2000 rules, we are trying for something that's more dynamic.