Learning to sail in middle age shouldn't be a problem at all... The problem will be remembering where you parked the boat...
Motorsailer is one of those terms that is hard to define very exactly. You young things really have no idea. When I was growing up we would rush from the cave and felt lucky, nay blessed, to make it to the shore without being taken by a velociraptor and we pretty much thought of any dugout with a paddle as a motorsailer...
[sorry I'm avoiding dealing with a broken valve at the bottom of a full holding tank
and I'm taking my humor
where I can get it].
However, there is a point, most boats that have cruiser anywhere in their description these days come with enough power installed (typically smooth, quiet and efficient diesels) to make them pretty decent motorboats as long as you're willing to motor at speed to sqrt(lwl) ratios of not much more than one. Cats under power have the advantage of having very limited roll. Not long ago the amount of power that is typical in cruisers today would only have been available in motorsailers.
There have been a number of motorsailer types since the first of the class were introduced in the early 20th century. Indeed they cover so much ground that it is hard to know what anyone means when they use the term. Very roughly speaking they come in "fast" (semi-displacement under power) and slow (full displacement
at all times). The slow versions often work quite well and they range from auxiliary sail to sail stabilized power boats. The fast version is a very hard design brief to do well particularly in a keel
yacht. These are probably the motorsailers that you've heard of that don't do either well.
might be a better platform for a fast motorsailer than a keel
yacht because it does away with the ballast keel and because slender hulls are less constrained by wave drag than wider ones. However, the weight and drag of the rig will always make it motor worse than a pure motorboat of similar type and it will add to the cost as well. Very large motors and their fuel will detract from performance under sail and also add cost. So even for a cat a "fast" motor sailer is a big ask. IMO, if fast is your thing it might be better to look at pure power and save the cost, drag and complexity of the sailing rig.
If you're willing to travel slowly then there are many boats that power and sail well. Many of them will not be marketed as motorsailers but would work well in that service
. At the distances you're talking about tankage should not be a major problem. At the slower design speeds there is almost an embarrassment of boats that I think will work for what you're asking for. As you demand faster speeds you will run into more compromises and costs. The cat you're looking at sounds quite powerful but there is little reason to believe it wouldn't be a lovely cruiser if you don't mind the expense.
For learning to sail I'm not a huge fan of big boats and particularly big cats. It can be hard to understand exactly what's going on and doing damage to people and property becomes a genuine worry. My preference is for learning in small boats -- doubtless because that's how I learned. Perhaps some lessons to get you started (maybe a crewed charter or two) and then keep a tender
that you can sail for learning while you're at anchor
or from your marina when you have an evening off.