Sourin Vagon has 310Mah (milliamp hours) battery. I bet you had to charge it a lot. Could be why they don’t last you.
The Nautilus 2S kit I linked has 2500 Mah. Or, you could get just the 2S tank and a different mod with more battery reserve.
The 2S is compatible with Nautilus BVC coils and Triton Mini coils. Of which there is:
.4 and 1.8 that comes with, plus..
Triton Mini:
1.8Ω clapton, which is how the coil is made and is better for flavor.
1.2Ω
.15Ω but that’s an Ni(Nickel) coil and is for temp control only, and SS is better if you ever what to try TC.
BVC’s come in those .4, 1.6, and 1.8, also .7. I never noticed a diff in 1.6 to 1.8 so I just used the 1.6
So, a lot of diff resistances to choose from. But that’s not the only thing that has a bearing on what the vape will be like. The power(wattage) adjustment, of which the pods are not adjustable, and air flow adjustments, have a huge impact. As does MTL or DTL. Wattage and air flow adjustments mean you can dial in the type of vape you get for each coil, instead of the single preset of the pod(other than diff coils). So the 2S provides a lot of options to find the vape you want. You can try the 2 coils it comes with without buying others, and I’m seeing coils for $10 per 5 pack.
If you want to stay with pod type Nautilus AIO has 1,000Mah, 4.5ml capacity, and uses BVC coils. Also has a some air flow adjustability.
BVC 1.6Ω is what got me off cigs and I vaped it on a regulated mod at 12w, for about 9 months till I moved on to sub ohm.