Correct- the Mac would still need a Windows platform to run Access.
The MS-Access runtime is a free solution for distributing Access creations without requiring each recipient to buy a copy of Access.
I suspect the issue with runtime installation blocking the IDE may be some registry entanglement(s) that give the runtime priority when a user has both a full copy of Access AND the runtime installed on a machine. The result is a very unpleasant and surprising loss of the development environment, even though it may have been working fine before the runtime installation.
Here is an older thread for Access 2010, but the difficulty persists using at least runtime 2016-
https://answers.microsoft.com/en-us/msoffice/forum/all/after-installing-access-runtime-2010-cannot-open/37c3c628-9028-431f-a18b-7d26508a8e63
I have not checked recently, but I believe the full Access system remains intact once the runtime is removed, although the 2010 response suggested the main .exe may be overwritten and thus need some follow-up repair or reinstallation.
And yes- there's no end to 'other problems that can arise'.
But- for several years until the present- the runtime has been a very useful no-cost solution to giving our users access to Access. Our Mac users connect to Remote Desktop Windows hosts where they run Access clients.
-Tom