Since you have easy access to the area where the work would be done, you need to do that part of it.
Here's what you don't get to do:
- Rework the kitchen countertop area, and refuse to upgrade the electrical because doinng a complete job of that would involve altering the fuse box, which is out of scope.
- Later... Replace the service panel, but refuse to upgrade the kitchen countertops because that would involve updating the backsplash, which was recently done, and doingit again would be madness.
- Result: total remodel, wiring still from 1949.
So yes. You need to do the work that is possible. That means installing all the circuits you are able short of expanding the scope of the overall project.
For instance you might run the new circuits to the old service panel and simply join the new wires to the same old breaker, so the electrical is functionally unchanged but is "new panel ready". Having 2+ circuits on one breaker is fine, e.g. A basement receptacle circuit that serves outlets on both sides of the panel.
An intermediate junction box would also suffice, but will not be as appealing since obviously, a splice is less desirable.
Aside from getting an approving nod from every inspecetor... This then becomes an upsell, "look, the work was done forward-thinking". $50 of Romex then becomes a $1000 value bump, simce the buyers will then presume all the work was done so thoughtfully.
Believe me, homebuyers and inspectors see plenty of half-assed work freshly done by people trying to sell. Whenever a homebuyer sees fresh work, they know it was done for the sale and it'll be the worst tenant-grade shlock job that they think will pass inspection. So unless you can show them the multiple new Romex runs, they will believe you did exactly your original plan.
A big annoyance for a busy chef is breaker trips. Heat-making appliancs in kitchens wish they had 2000-3000 watts (and they do in Europe). But in America, UL limits them all to 1500 watts (12.5 amps) and obviously two won't fit on a 20A breaker. *That means a kitchen wired to bare code minimums can only support two countertop appliances at once, and the chef has a 50/50 chance of tripping the breaker anyway.
My answer is more circuits. The cost is only $10 for the cable plus a $20 GFCI per circuit. I would have one receptacle per circuit up to four, then leapfrog them, so same-circuit receptacles are not adjacent.
Now, when you're selling this house, you ask "who cooks?" and tell them what you did and why. If the chef has veto power... You just sold a house.