Even if he got a golden form...pretty sure that Frieza upgraded his version...during his death....he's now can control his power fully AND golden form now doesn't drain his power that much like it used to be...
Frieza has indeed gained control over golden form to have less stamina drain.
However Frost would likely still be stronger if he obtains his version of golden form.
Even if he has more stamina drain.
Although we wont know yet if he has more stamina drain if he gains the form.
Universe 6 ppl seem to have less trouble transforming and handling their transformation.
At least the saiyans from universe 6.
Their base forms are also super high.
Cabba base was equal to Vegeta base (who has trained under whis and achieved god ki).
In Frost his time surviving as a known criminal after the uni7 vs uni6 tournament, Frost his base went even higher (it was already higher than Frieza at the uni7 vs uni6 tournament).
To the extend that he made Hit use his full power for a moment, in their short fight when Hit went to recruit Frost for the tournament of power.
Even if Frost has more stamina drain in his golden form, he would still be a danger to Frieza as he will likely have more power until enough of it is drained.
They are both backstabbers, so it would be interesting to see how this will play out.
As they seem to have some agreement of working together.
However both probably do not intend to keep it, when its in their benifit to backstab the other one.