There are so many factors to consider and questions you have to answer for yourself.
You cannot have just one donkey. They’re herd animals and need companions. Other animals like a goat or cow might be good enough companionship but I would never suggest that. You will find stories about donkeys living alone happily but they’re a rare exception to the rule. I would question if the people claiming such have a good understanding is equid behavior.
Donkeys don’t need a ton of food but they do need it constantly. A few acres of land with edible plants is more than enough for a donkey to eat. It’s harder to keep a donkey thin and healthy than fat. However that depends on where you live. Will you have year round edible plants or will you need to buy hay in the winter? What is the price of hay in your local area and where would you buy and store it?
Donkeys need to have their feet cared for regularly. It’s entirely possible to learn how to do that yourself but what is the availability if it’s something you can’t handle? This depends very much on your local area.
Medical care is a very complicated issue. There are regular vaccines and care that every equid needs. Those aren’t very expensive and usually easy to access. Emergency care depends on your local area. If you are very remote then emergency care is whatever you can do personally. Getting outside care will be very expensive and a long wait. You have to consider what level of medical care you are able to provide and decide if that is acceptable to you.
As the donkeys get older their care will become more complicated and expensive. What level of care are you comfortable and capable of providing? How will you deal with serious issues that arise?
Living a rugged individualist lifestyle in a remote place is a totally viable strategy for some people. Donkeys do very well in rugged remote places. Millions of people around the world depend on donkeys to survive.
It sounds like you are looking for a pet and not working livestock though. That means you have to decide if the lifestyle you can provide a donkey is acceptable to you or not. What happens when something expensive comes up and you simply can’t afford it? What happens if your circumstances change suddenly? What are you capable and willing to do when there is a medical emergency and help is seven hours (or seven days depending on how remote you are) away?
If you have more specific questions I’m sure someone or myself can answer them.
I’ve been using freecad for several years and it has improved a lot. I tried fusion and sketchup and a few other “freemium” options but features kept disappearing into the paid section so I decided to stick with something actually free and learn it.
I use the two dimensional sketcher the most. Find some tutorials about using constraints properly and it is very easy to use. The tech draw workbench lets you add dimensions and information in a printable format. Figure out how to do 1:1 scaling with your printer and you can make templates with perfect accuracy in minutes using only a few key dimensions.
Assembly is still a complicated process though. The assembly 3 and assembly 4 workbenches are great but pretty arcane. I don’t remember which one I used last time I did a full multipart plan but the result was great. Basically they let you create anchors on lines and vertexs and such that then interact with each other across parts.
The trouble is in how those anchors interact with their parts. If you round an edge you just made some lines shorter. Was that anchor point attached to that line? Now it’s in a different spot. Essentially you have to be perfect every step of the way and plan ahead or change many things for even a tiny change like a round edge.
With a little practice I’ve been able to get the assembly benches to make great results. You really have to do it correctly though or it all falls apart. The lack of in depth tutorials means you have to make a lot of mistakes and learn from them.
I would suggest trying freecad with either assembly bench. I’m not sure which one would be better suited to your needs. If it doesn’t work for you paying for sketchup or fusion might be a better option. I think in a few years freecad will be very competitive but for now it lags behind on ease of use. Sometimes by a lot.