Disposables have a place in the market but, for someone already using refillable devices, not something to use regularly, imo.
Your Nord GT probably came w/ a manual that should tell you how to lock & unlock it. It may be faulty, though.
If you want longevity, i'd suggest you consider getting a mod kit that takes a separate battery rather than a built-in battery pod device. There are many options from several companies.
You mentioned Vaporesso. Their Luxe & Xros pod kits have good reputations but maybe you should consider something like an Armour S kit. They're built to be durable & the coils are known for great flavor. i'd bet it would last you much longer than any SMOK pod device.
Other companies have good reputations for durable, quality products, too. Innokin & Eleaf are 2 of them. Innokin's Coolfire Z80 or Eleaf's iStick Pico Plus kits are both small & light -- like pod devices -- & might serve you well. Vapefly's Kriemhild 80W kit is a very simple, variable wattage only, device that comes w/ a pod-tank (sort of a hybrid of a pod & tank). The manufacturer is known for quality & a kit like that could suit you well.
If you're willing to spend some real money, there are mods not made in China & known for longer-term durability. Dicodes has a great reputation, for example. Their Danibox Micro + any decent tank might work for you if you're okay w/ paying for higher quality & dealing w/ a little more complexity.