Is university teaching better than high school teaching experience in applying for teaching-funded PhDs? When applying for graduate assistantships or part-time teaching for grad school scholarships, is university teaching necessarily better than highschool teaching experience? if so, by how much?

Possibly relevant details:


I am graduating soon with a master's degree from a third world university.
My plan is to get a PhD but am considering getting teaching experience to boost my chance's of getting in.
I am considering teaching at my university (or another university in my country) for a year or so.
However, I have something like a dual citizenship in a first world country in the sense that I permitted to work there in addition to an established residence (my mom and sister live there while my dad and brother live with me).
Said FWC is where I would like to get my PhD.
My parents suggested I teach at my sister's highschool (or some highschool in said FWC since I will unlikely get into one of the universities there).
I am fine with either in terms of job requirements (e.g. highschool has more requirements and students tend to snooze off more), but the pay is alarmingly different by a factor of 5.


Another difference is that if I teach in my university long enough, I might be able to teach or assist in teaching advanced stuff like probability, linear algebra, calculus III or financial maths. There's also a tutorial center nearby and there are occasional students who need tutorials in probability, statistics and linear algebra.
If there is an option definitely university teaching is more valuable as it is at the same level as the teaching you will experience while doing your degree. However, you should consider that PhD is a research-based degree and teaching obligation is not primary concern. So you might get the position without having any teaching experience and finally get your PhD being a year or so younger.