An April trip means you can take advantage of German Railway's springtime rail pass sale. How many is "we"? A 3-day flexi twin pass for two adults costs €270 at DB if you buy by March 31.
Click on "book now" under "Flexible travel days" to see the prices for the twin passes:
https://www.bahn.com/en/view/offers/passes/german-rail-pass.shtml
You'll find that trip costs vary by date and travel hour for the p2p tickets at DB. Once you total up the costs of p2p tickets for those trains you want at the time you want, you'll see whether €270 is roughly competitive or not. There's no way to say until you check. Of course there's still a qualitative difference - with the rail pass, you can use ANY trains you like at any hour on your three planned travel dates (or on other dates instead.) With the p2p saver fares, you commit to those specific trains at the time of purchase.
If Frankfurt > Munich means you are leaving from Frankfurt Airport after a transatlantic flight, the rail pass has a particular advantage since you can hop on any train whenever you're ready to leave - whether your plane is on time or not. With the train-specific, advance-sale saver fares that Jazz+ recommends, a flight delay or other delay could mean you'd need to buy new tickets at a higher price.
