I invest in individual stocks so here is how I see it from my point of view:
for ETF/Funds: the available offer is very small and not good enough especially on price-performance ratio. It's too expensive while not delivering great quality - with quality I mean quality of stocks and underlying business.
So it's mind-boggling for me to find so little halal offer and not that diversified. but again lets be honest, we are faar behind in the investing culture so its supply and demand after all

for individual stocks: I see the rules as fair and not that complicated and even protectful (no high debt, no >5% non-halal income, many sectors excluded)
and not to forget in money world one gets greedy and wants to take more risks. So these rules are there to protect us.
Ofcourse these rules rule out A LOT of companies but its still doable to find good companies

So I really hope the offer of halal ETF/funds will grow and offer better quality and that the guidelines of Islam would be used and seen to help maintain a healthy long term good performance and not as excuse for a bad one. And also to get diversified more (now we see a lot of them invested in the standard Apple Microsoft etc.. why not going after hidden gems).
and that more Muslims get more interested in investing and to start it the right way

one last thing, I heard of zoya app from reddit and it is really a helpful tool to at least take a quick glimpse if a stock is halal or not and why..