Recycling isn't really a pickup problem but a commodities pricing and market forces one. Most of that stuff is worthless because it costs more to recycle than it does to make them new. So we end up subsidizing them for the feels while ultimately accomplishing nothing.
Some materials are worth it (aluminum) but a lot of it just gets dumped in poorer countries after sorting. It's just a way for first world nations to export their waste streams while lessening consumer guilt over single use items. Because environmental protections differ so much between countries, it's often cheaper (but environmentally worse) to export those materials than to just bury them here in modern landfills. Problem is, once they're exported, our environmental regulations no longer apply, and they're free to be dumped in the waterways or in poor villages.
I'd say overall recycling is a scam, and making pickups easier would actually worsen climate change by encouraging individual pickups (Doordash style) instead of a shared route on fewer recycling trucks (UPS style).
That said, the waste management industry as a whole (bigger than recycling) is interesting, like landfills and incinerators and mob contracts and zero waste diversion quotas etc.
Climate tech is booming though, everything from batteries (especially) to solar PV "balance of system" components like inverters. There are also niche companies working on algae and hydrogen and of course wind, etc., but by and large solar PV seems to have won out in terms of dollars.
There are a few software companies working on streamlining the design and permitting processes, using a combination of aerial imagery and photogrammetry plus human design to automate rooftop solar module (panel) layouts for optimal production, and making applying for permits easier. Google's Project Sunroof is a good example of the former tech, and Aurora and Opensolar are examples of more integrated design project management solutions.
Beyond low hanging fruit like that, there are of course the much harder problems of battery chemistry (and storage in general) , EV charging networks, nuclear acceptance, megahydro removal, micro hydro for communities, etc.
Check out Appropedia.org sometimes for a wiki of DIY sustainability stuff that people around the world are tackling. Might give you some ideas?