You do have some points, I'll give you that, but here's some more context for you:
Ronaldo had that nice backheel to Sancho, that gave Sancho a 0,13 xG-chance. The 2 he had against Brighton was much better, and on average 3 passes like that would end up in 1 goal combined (1,12 xA). So yeah, it could have been three if every chance were converted. This season Ronaldo has produced and xA of 3,55 and his teammates has converted 3 of his passes to goals. 0,55 goals less than expected over the entire season, so it's not like his teammates has massively let him down. The funny thing is that in the 20 games he played before that Brighton game he had produced a combined 2,32xA and his teammates had overperformed a bit up to that.
The most common way to define a players actual goalthreat and contributionrate is to add up his non penalty goals per 90 with his expected assists per 90 (npG90 + xA90). That way you measure only the factors that the player can influence himself (his own finishing, but not his teammates finishing). In the PL this season Ronaldo has produced a goalthreat of 0,54 npG90+xA90, which places him 26th in the PL for players with 500 minutes or more this season, and 3rd in our squad, behind Bruno (0,7) and Rashford (0,69).
For comparison with the best of the best (npG90+xA90):
Salah (1,00), Mbappe (0,85), Lewandowski (1,3), Haaland (1,29), Benzema (1,04)
It's quite extraordinary for a player with only 3 players above him in npxG90 (Salah, Mane and Jota) and only one player above him (Salah) in shots per 90 in the entire league to have the 26th best actual goalthreat in the league. His finishing has been that bad in the league this season.
Take away the first 2 games (Newcastle and West Ham) and the Brighton game, and he would be outside the top 50 in the league based on the other 19 league games (0,37npG90+xA90) this season....
Then comes the lack of defensive workrate and the other parts of his game that leaves a lot to be desired.
He's still very good at making himself available for service, but that is pretty much the only thing he does well these days.