The Denon DRA-F107 has not been available as a separate product but only bundled with the DCD-F107 CD player and SC-F107 speakers. The entire set sold for roughly 650 € (list price, street price dropped below 450 € a year or so after introduction). And it was made roughly 15 years ago.
How can you know
for sure the Denon is at "least (bold!) as good as the WiiM Amp", just because the WiiM amp is so "cheap"?
It's not perfectly clear to me if you got it that the Dali speakers did not originally come with this amp. We can still conclude that there's no
obvious problem for the DRA-F107 driving them, if
@Giro413 has been using this combo for a while. I did not find any measurements of the Lektor 2 specifically but Dali has a reputation for making easy to drive speakers. Nominal impedance is 6 ohms and them being small and simple 2-way designs we shouldn expect them to be a non-critical load for most every amplifier.
Some pros for the Denon (e.g. more versatile remote, more legacy inputs, ...). Some pros for the WiiM Amp (e.g. more power, feature-rich streamer and decent DAC already included, 15 years younger design, somewhat basic but vastly superior subwoofer management, EQ, ...). Just for subwoofer management and EQ alone I would probably give the WiiM Amp a try.
I won't pretend I can predict the outcome but personally I'd be willing to take that risk.
Con for the WiiM Amp: DAC not exactly on par with the WiiM Pro Plus, so replacing the Denon with a different higher quality amp-only device might yield even better results (at the expense of more clutter compared to WiiM Amp). It all depends on what you want.