I get where early LEDs didn't make much of an impression, with their blueness and rather terrible CRI. That didn't just bother you, it also bothered people in the LED business. As a direct result, they fixed it. Very thoroughly.
Of course it's still possible to buy cheap, janky LEDs; in fact it's pretty easy. All the usual cheap outlets await. However for the discerning buyer, it's no trouble at all.
Incandescents are a firestarter here
The entire point of a GU24 fixture is to render it impossible to insert incandescent bulbs. And I know this seems like a big dirty government conspiracy, and I won't deny that energy conservation and pollution control have a slice of the pie. But a big part is manufacturers themselves are happy to be free from the thermal management challenges of building a fixture that takes incandescents.
Is there a risk of fire because the fixture can't handle the heat?
Correct.
What if I remove the glass fixture?
How about the wires / sheath?
We don't know because in this country, we have someone who answers those questions for us: Underwriter's Laboratories or UL. UL does all this testing on the fixture, and gives definitive answers to all these questions. However, the UL listing is contingent on the fixture being used according to its labeling and instructions.
(UL has competitors; CSA and ETL are common ones, and expect to see a file number as part of the label. CE is not one; it stands for "Chinese Excrement" and is found on the rubbish from Alibaba/eBay/Amazon.)
Because of that, a UL listing is required for fixtures installed in homes (NEC 110.2). And you are required to obey the labeling and instructions (NEC 110.3b). We here have had a lot of experience with the electrical codes (NEC) - and our experience is that every rule in there has a good safety reason for being there. There's no government conspiracy; it's written by a nonprofit. So the NEC is something we take seriously, and you should too.
Insurers agree, by the way; they'll refuse a homeowner claim if it's caused by an intentional violation of NEC.
Change the fixture
Fortunately, Home Depot has loads of fixtures with E26/27 sockets and rated for incandescent, that actually do have proper UL/ETL listings with file numbers. Buy one, put it up, have a field day with your incandescents.
This may violate some other codes, but they're not safety codes, so that's between you and the regulator.
Re-factor your circuit load
Another reason builders use guaranteed-low-power fixtures is it allows them to put more fixtures on a circuit. So, identify your circuits and re-crunch your numbers to make sure you aren't inadvertently putting 2300 watts of fixture on a 1440 watt circuit.