A leaker has outlined early details about OnePlus' plans for its next-generation flagship smartphone. Due towards the end of the year, the OnePlus 15 is rumoured to feature upwards of a 20% larger battery than the current OnePlus 13.https://www.notebookcheck.net/OnePlus-15-Huge-battery-gains-revealed-for-next-gen-flagship-OnePlus-smartphone.1022331.0.html
It needs it. In your review of the OnePlus 13, you even saw it in your test results (Power Consumption.) While Oneplus phones do have stellar batteries and charge times, they need it because they also have some of the highest power consumption levels of modern flagships (came in last place in your test.)
Have a 12r and while the charging speed is fantastic, it often needs that touchup before a full day's use.