In my application a cards are used and they their color equals several states
each color has a meaning ea red is error , green is okay, and some more.
this is done by angular logic and [ngstyle]

'background-color':
                          getSelected() ? '#158917b3' :
                          carStore.hasAlarm ? 'rgba(220,53,69,0.15)' :
                          carStore.status && carStore.isOnline ? 'rgba(40,167,69,0.15)' :

Now in each card a striped table is shown in, there we see some text and numbers.
This table striped had colors of black assigned set in transparency values.

I came from bootstrap 4 and recently upgraded the site to bootstrap 5.3

If i now set the transparency of the table in css alike

.card .table-striped {
  --bs-table-striped-bg: rgba(0, 0, 0, 0.5);
}

.card .table-striped > tbody > tr:nth-of-type(odd) {
  background-color: var(--bs-table-striped-bg) !important;
}

.card .table-striped > tbody > tr:nth-of-type(even) {
  background-color: rgba(0, 0, 0, 0) !important;
}

Then it ignores the background completely, it just shows white and gray. (not what i call transparency?)
I tried some other variation of the css syntax though i don’t get the transparency effect to behave as before.