alternate multiclassing (optional rule)

this is a optional rule that allows you to multiclass in two extra ways (i didn't see a optional rule home brew option, so i listed it as feat). You can still multiclass in the normal: when you would gain a stat bonus you can instead gain another class. The first way this rule allows you to multiclass: is by reading a class book, After 30 to 40 days worth of reading the class book during a long rest, you gain said class. The second way this rule allows you to multiclass: is by going to a trainer. After 20 days you learn the class.

other things: any class you learn starts at your highest leveled class minus two. and to learn a class you need to have a 13 in that classes' primary stats to learn the class (strength, and constitution for a barbarian, for example).

With this rule, gaining XP is changed depending on your primar, secondary, and other classes. XP gained for your primary class is the same as normal but your secondary class gains 25% less XP,  your tertiary class gains half as much XP, quaternary class and onwards gain 75% less XP (if you gain 1000 XP the Primary class gains 1000 XP, your secondary class gains 750XP, your tertiary class gains 500XP, and your quaternary class and any other class' gains 250XP, you do not lower the XP amount any further even if you have a quinary or senary class). You can switch your class order during a long rest (in other words when you long rest you can change which class is your primary, secondary, tertiary, quaternary, and any others).