I have v5.1.2 too but spent lot of time to compare v8 and v4 with lot of plugins and versions. So v8 compared to v4.4 is much faster though a less reliable but noticeable convenient. Moreover lot of plugins denied to work with v4.4. But several themes showing with formatting errors. I bet lot of customized themes and plugins should be rewritten but so be it. And v8 works with php8. So you decide.