It depends of the rim, the issue is that u have to pick to get the tension right and kind'a even in all the spokes or have the rim 100% true in the wheel. Sure the rim is not that good and u have problems of tension now. For the record rims arent always straight.

I would tension the wheel as much as possible and leave the wheel kind'a true.

If the wheel is true and u have lose spokes is clear the rim is the problem, u can wack the rim to fix that but if you dont know what are u doing u can damage the rim big time instead of fixing it.

Good luck.