You can Start a Shortcut with Pythonista:

import webbrowser
vUrl = 'shortcuts://run-shortcut?name=testStartWithUrlScheme&input=10'
webbrowser.get('safari').open(vUrl)

Maybe you can split your Shortcut into 2 different Shortcuts.
This should work, if you use Url Scheme on both sides.
(it's not really in the Bachground, as cvp mentioned)

This works for me, the script is in This iPad/dir:

The iCloud Path should be:
/private/var/mobile/Library/Mobile Documents/iCloud~com~omz-software~Pythonista3/Documents

but i dont use parameter

Edit:
Did a test for parameter with url scheme:
see here: Pythonista Url scheme

works too

Not iPadOS 14. Nothing is working. 😩
The only Safari Link i get is:
localhost:49402
second try:
localhost:49404

then yes :)

@DavinE,

I think it is a Pythonista Problem with iPadOS 13+

Btw: you have 2 different Browser:
iPhone: iPhone (with standard mobile Websites)
iPadOS: Macintosh (with standard desktop Websites)

@mikael, as i write FTL :)

@Niklas, my Solutions sort on:
First: 3 digit numbers, leading zeros
Second: Character

This are the sort keys (not sorted):

009Sö
011Sö
215U
005M
016M
000
010M
001M

They have all different Numbers, so charakter dont care.

You can change the regex to whatever you need.

I had a similar Problem. I need a german sorted List and locale didn't work with Pythonista. So i have to write my own Sort def. That should solve your Problem.
But @mikael was faster than light

def myOwnSort(vInput):
    import re
    
    vInput = dict_nested[vInput]['sv_runinskr_trim']
    vInNr = re.findall('\d+', vInput)
    vInNr = int(vInNr[0]) if len(vInNr) > 0 else 0
    vInNr = '{0:0>3}'.format(vInNr)
    
    vInChar = re.findall('\D+', vInput)
    vInChar = vInChar[0] if len(vInChar) > 0 else ''
    
    vNewSortKey = vInNr + vInChar

    return vNewSortKey


TheOneAndOnlyNewAndPrivateSortedDictionaryWithMyOwnSortKey = sorted(dict_nested, key = myOwnSort)


for i in TheOneAndOnlyNewAndPrivateSortedDictionaryWithMyOwnSortKey:
    print(dict_nested[i]['sv_runinskr_trim'])

Still not working, really?

@mikael: jesus and wtf and a lot more... :)

@Seb,
I come from Basic (ZX81) and be sure i know nothing about best practice. I have only some experience.
Changing the same variable within 2 defs at the same section of code is a good error source.

And for Return, its easy you just return a value (or more).

def function1():
    variable1 = 'Hallo World'
    return variable1

def function2(str1):
    return 'Hello ' + str1


print(function1())
print(function2('World')) 

Some thoughts from my Side:

You can iterate your Str keys, no need for keylist.
In your Function you create a local variable sameletter. You dont change your global Variable.

Add: global sameletter
at the start of your functions
or work with return

And i dont like the Idea that there are two functions, called directly one after one, and both change the same variable. I think one function is better.