How to run multiple RecurringJobs synchronously to eachother?

You have many options.
You can make them as delayed jobs and have current job schedule the next one.
Or you can make them fire much more often but check if the other one is running.
Or you can add a key to the hash table of hnagfire and make the other job wait until it goes away.
Or you can use Hangfire.Pro that has continuation.
Or something like Specify a Continuation on a RecurringJob