Morocco ferries have been running for over a year now, just not the ferries from Spain. Current access is via France or Italy on a long and expensive crossing. Then you need to add in to the equation that if you travel from France its a List B country so if Vaccinated you need a PCR test timed within 48 hours (the ferry takes 40). If unvaccinated you need a PCR and 10 day quarantine on arrival. Sadly Morocco is a dead end with heading further south at the moment with Covid restrictions. Theres a small possibility of crossing into Mauritania but its risky and expensive.
Best to have a look at some of the region specific sources of information rather than on here. If you're on Facebook the Overlanding North Africa Group or the Overlanding West Africa and Morocco Group are by far the best and probably the only ones with members with detailed, up to date local knowledge. Theres a few other copycat groups but they have limited expertise.
The Hubb regional forums are OK but lag behind on recent info and that's got worse with covid. Chris Scott's Sahara Overland site provides clear concise summaries of info received from recent travellers and his own trips to the region. For the Sahara as a whole Chris is probably the most knowledgeable person out there but even he gets info from others who know more than him in specific areas.
Sadly the golden age of Trans Sahara travel of the 80's and 90's has long gone with the growth of Islamic extremism, smuggling and banditry in the Sahel. It'll be many many years before this sort of travel is possible again.
Ignoring COVID restrictions the longest trans Sahara trip possible in some safety is Tunisia - Algeria - Mauritania - Morocco. Otherwise, with the exception of Egypt its all a no go zone. Tunisia is straight forward enough, as is Algeria until you get about half way south, then you'll need Police/military escorts or guide. Crossing into Mauritania takes you in to a Red Travel Advisory zone for about 100km or so, from there its a 1000km of desert with no facilities and no help if things go wrong. go too far south and thats Jihadi territory, go to far North and that's Polisario land. From then on its, relatively speaking, plain sailing.
There are hurdles to overcome with Visas, depending on which passport you have. For UK passports getting an Algerian Visa is a lottery, some get it, some get refused with no real reasons. Travel Insurance will need a specialist company to deal with the Red Travel advisory areas, but Battleface should be able to provide cover for a fee.
Charity work is all good but best to work with a known charity in the country you looking at working with. Morocco got particularly sensitive after a number of people were killed in a stampede when a well meaning soul starting handing out clothing in 2018. Mauritania should be OK and I'm not sure about Algeria or Tunisia on that front.