For starters, go into game options and switch to the movement controls from standard to alternate. It feels much better that way.
Does all your equipment have durability? Yes. Everything will degrade over time. Except probably the crossbows. That said, your armor will only degrade when you're actually taking damage, so once you get better at the game, you won't have to worry about repairing armor all too often. If you're struggling with dodging, Quen is your friend. Swords are going to need pretty regular upkeep though. If any of your equipment degrades to the point of breaking, it's not really a big deal (beyond the obvious protection loss on armors, and the fact that you won't be able to use your swords), it just means they'll need more repairs. Meaning either more money spent at a blacksmith, or more/higher quality repair kits used.
I would recommend a playstyle with a healthy mix of combat and alchemy abilities. Frankly, it's both more fun, and more effective than going too deep into a sign build, which relies almost entirely on spamming everything with Igni all the time. Throw a few points in some complimentary signs if you want, but they'll serve their complimentary purpose just fine even if you don't upgrade them at all, really. Better to spend some time making sure you're getting as many alchemy recipes as possible, as they'll provide very nice buffs for the various enemy types, and increasing your toxicity threshold allows you to have multiple active decoctions, which can really supercharge your combat abilities.