How can I provision more CPU from VMware when MAXDOP is set to 1?
Are all of my assumptions above correct?

Yeah, you're correct on all counts as far as I can tell.

If so, does that mean there is no way to boost the CPU available to these queries?

Given the constraints you've described, the only way to &quot;boost the CPU&quot; for those queries would be to move the VM to a host with a CPU that has a faster clock speed.

Is there anything else we can do?

Your best bet would probably be to identify the problematic queries and set up plan guides to add MAXDOP hints to those specific queries.  This will override the server level setting, so those specific queries would go parallel, while the rest would still be at DOP 1.
Some other options, that are less ideal / more likely to cause problems:

Increase server level MAXDOP from 1 - this goes against the config guidance of course, but it is an available option to test and see if it benefits these problematic queries without causing much harm to other queries
Add more CPUs - this doesn't help individual queries that are CPU-bound, but it will allow more queries to run at once potentially.  This could help or hurt depending on the details of the workload.  For example, running more queries at once might just lead to contention (locks or tempdb or something else) rather than increased throughput