This is why we have the EU.

For context, the EU has lots of competency in labor law. It's a protection against dumping since free movement was introduced in the 1980s. There is the Charter of the Fundamental Social Rights 1989 and then a bunch of directives. Any EU directive automatically takes priority over national law.

Some examples of well-known directives:

The Safety and Health at Work Directive 1989 requires basic requirements to prevent and insure against workplace risks, with employee consultation and participation,[18] and this is complemented by specialised Directives

The Working Time Directive 2003 requires a minimum of 4 weeks (totalling 28 days) paid holidays each year,[14] a minimum of 20-minute paid rest breaks for 6-hour work shifts, limits on night work or time spent on dangerous work,[15] and a maximum 48-hour working week unless a worker individually consents.[16]

The Parental Leave Directive 2019 creates a bare minimum of four months of parental leave

IMO any foreign companies are welcome to do business if they respect the law.