Playing with encryption

I've been playing around with some encryption methods over the years that I had never found before. I'm curious if someone with code breaking experience can try cracking my different codes and tell me how difficult they seem.

Each different code is a different iteration I've come up with over time. Listed chronologically. I'm curious if the difficulty increases with each iteration. Please don't share craked messages or codes in comments, just their difficulty in your opinion.

1. Yjod od yjr gotdy hrmrtsyopm vpfr.
2. Ikqf qf iky fyvwmg jymyudiqwm.
3. Ysr ysotk zrt O hkkrk h fru.
4. Yftk hpn r saaof k hou ltnojkp yy k ypjejaufj.

A friend introduced me to the following two by accident:

1. Yjod esd yjrot ofrs, mpy qivj foggtrmy.
2. Ikym A fdt ikqf.

I could also do versions of 3 and 4 with their idea but I have a suspicion the first versions are more secure because of how I'm using them.

Thanks for the time and God bless!