[TS Migration] Improve how Routes are validated

[mountiny]

Follow up issue for TS migration project. Coming from this spreadsheet

Improve how Routes are validated (use AssertTypesEqual util)

cc Any more details to share here? @blazejkustra @fabioh8010

[smelaa]

Hi! I am Aleksandra Smela from SWM, an expert agency and I'd like to work on this issue.