@AndreaC74 sorry, I know the replies make posts and replies about points a bit more complicated,
Regarding the % of oil and gas in pension funds, I couldn't see a definitive answer. I suppose it might depend on the agenda of the person answering though someone in the pension industry could presumably give you a simpler, definitive answer. Different funds have different investment strategies but I've seen 0.4% quoted on the context of a body advocating a windfall tax and trying to counter a 'this will hit pensions argument'.
I've seen absolute figures of $1.4tn of traded company (non state firms) oil and gas assets held by financial institutions and at one time this equated to the total UK pension fund assets though there will be lots of non-pension funds that hold these assets and pension funds hold other shares as well as bonds and alternative assets. This was by someone discussing stranded assets if the economy goes green and half? this $1.4tn becomes worthless. Some were giving these figures to encourage divestment by pension-contributors and some were saying be careful of going green and sabotaging pensions. It seems contested.
I recall hearing that pension funds prioritised dividend-paying stocks which included extractive mature industries pre-COVID though i understand the investment strategies are incredibly more complex than that.
Regarding the subsidy or not, this might depend on perspective. Some will see a clear subsidy, some will see a cost that needs to be considered before profits and tax can result. I think the decommissioning costs for nuclear are so high that these have been taken by the state even for commercial providers though could be wrong.
I suppose the advantage of France retaining state control of EdF is that they can impose a hard cap with a 4% increase then make the numbers work behind the scenes. I have a little sympathy for the smaller UK firms that had to buy in the market rather than having an extractive arm as the price cap led them to having to buy energy in the market at a higher price than the government let them sell it leading to liquidation. I think there was little appetite to take on the loss-making customers of one of the larger failed firms and the government had to run it itself. I know with hindsight they should have hedged the liabilities but it seems unsatisfactory in a commercial market for the government to impose the hit on a small firm doomed to crash.
As PPs have said, Norway created a state fund worth £tns whereas the UK used the revenues for tax cuts and subsidies. Hindsight can be easy.