Back linking questions

I have two company websites with close affiliations to one another, both have separate names and branding.

For example purposes:
Lets say the parent company is called "WeKitchen" which offers a complete bespoke kitchen service, and the sister company is called "CabGuard" which offers pre-made, flat packed cabinets.

WeKitchen is self hosted and CabGuard is on shopify.

Essentially, I'm creating anchor text links from WeKitchen project pages to a CabGuard product pages.

BUT.. When I'm linking from WeKitchen to CabGuard the links are being ignored. Only the links appear in ahrefs when I'm linking from CabGuard to WeKitchen... which I don't want.

Q: Are there self hosting issues that can stop google crawling back links?

I also have regional sites for the CabGuard company i.e "com" & ".com.au" (example only)

Q: I want to link "Warehouse locations" in each footer. Should these link with "nofollow" tags?