Regular Nisa or つみたてNISA -> What is the right choice?

[RetireJapan]

what does that mean? After the first NISA expires I could take all what's in there and start a new 5-years NISA?

Each NISA year is treated separately, it is not the case that the account as a whole is treated as one. So you could roll over each year as it expires, assuming there is an equivalent NISA available to roll it into.