We do not know how the situation could look like : sometimes half the trains still run, sometimes the whole network comes to a halt (depending on who is striking).

What we know : the last times strikes lasted 24-36h max but now they have the green light to make unlimited strikes.

I don't think you'll get any compensation for a rental car (especially if booked before the strike begins). International one-way car hires are also very expensive.

What you could do is travel in Switzerland as it's the most logical country between Strasbourg and Munich.

Then book a bus from Zurich to Munich if it's certain that the trains won't run. That way you don't have to avoid Munich/cancel the flight. That's what I'd do.

First - thanks for reminding me about the strike.  We will be passing through Germany later this week and back the following week, so this reminded me to check all the options.  I think we will be OK though.

Second - you need set your priorities very clearly in order to decide the best option.  If it was me bringing my family on a holiday then I would change plans, refund the hotels and head from France to Switzerland/Austria as suggested above.  You don’t need (or want) to be reliant on a network that is on strike if you have a pass that lets you change country at will.

Given the season that’s in it, the ride from Zurich to Innsbruck should give you some great views of the alps.  Plus, you get to add another country to your list as the train passes through Liechtenstein.  And finally . . . once you are in Austria, the connection up to Munich should be much more achievable so you you can still get your flight to Dublin.

However, if Germany is an absolute must (like because your family came from there or something like that) then you need to prioritise that bit.  I would still avoid a country with a rail strike when on a rail holiday though.  Maybe go somewhere bordering the area you are interested in and then work out how to get alternative local transport into Germany.