@EnjuAihara
setxkbmap -model pc105 -layout is,ru-is -option caps:swapescape grp:rctrl_switch grp:shift_caps_toggle compose:sclk shift:both_capslock

look at the -option part

caps lock = escape
shift+shift = caps lock
escape = caps lock
shift+gaps = change layout
scroll lock = compose key (compose+a+e = æ, for example. lots of useful combos)

@applejack
y is y
i press shift + capslock
y is z
i press shift + capslock again
y is Z
and scroll lock eats my letters

@EnjuAihara you need to tell it to use your own layouts. and heres a list of compose keys, but you can also create your own (h+h=卐)

@EnjuAihara forgot to actually link the list https://fsymbols.com/keyboard/linux/compose/

@applejack oh
esc and capslock switched bc you use esc more often and caps is easier to press
ive heared that somewhere before