I think the advice you've gotten for a starter mech is good. You certainly can go with your preference, just make sure your build is safe, you understand your battery's capacity and how to achieve it and that you have an authentic battery and etc.
There are single battery mods, they tend to offer better hand feel, and be less bulky. If you want to vape a low resistance you have the opportunity of doing that, and many of them are near indestructible. The single battery geekvavpe ages for example it's designed to be dropped, run over, dunked in water, and keep ticking and it is far, far safer than a mechanical mod.
I understand why mechs can be appealing, and I have a couple stashed that I will bring out if I ever need them, but I also have a ton of very durable, long lasting vape gear (and I am hard on mods) so... Saying "regulated is going to die," well, eventually it may do so. Mechs equally require ongoing care and maintenance, so it is sometimes six of one half a dozen of the other.
Also a regulated mod can be much handier than a mech at times. Out and about, mech mods can be kind of a pain at times, and also require a lot of knowledge and safe handling.
I'm not saying don't ever buy a mech or use it, I am pointing out that there are regulated options that are as good as, if not better than, a mech under certain circumstances.
You don't HAVE to jump in at the deep end, and if you do, you are more at risk of drowning while you learn to swim. Because safely using and operating a mech as an all day vape, that is a lot to learn right there.
If you are hellbent on one, well, read up in the mech mod forum, on battery safety, and everything else required to use one successfully. Which does take a certain amount of time, and while I certainly feel that everyone (who has the ability to use one) should own one, that doesn't necessarily mean that regulated devices are not useful, durable, and far safer to carry about than a mech.
Best of luck,
Anna