Loans and Borrowings - Schedule of Principal and Interest Payable Outstanding Amounts (Details) - EUR (€) € in Thousands	9 Months Ended
Jun. 30, 2024	Sep. 30, 2023
Disclosure of detailed information about borrowings [line items]
Senior Note embedded derivative	€ 28,638	€ 28,638
Less: amortization under the effective interest method	(19,342)	(46,163)
Non-current liabilities	1,325,221	1,815,695
Current liabilities	€ 17,140	37,343
Term Loan \| EUR
Disclosure of detailed information about borrowings [line items]
Borrowings, maturity	2028
Non-current liabilities, gross	€ 375,000	375,000
Term Loan \| USD
Disclosure of detailed information about borrowings [line items]
Borrowings, maturity	2028
Non-current liabilities, gross	€ 304,120	730,159
Current liabilities	€ 3,061	7,347
Vendor Loan \| EUR
Disclosure of detailed information about borrowings [line items]
Borrowings, maturity	2029
Non-current liabilities, gross	€ 208,305	299,560
Senior Notes \| EUR
Disclosure of detailed information about borrowings [line items]
Borrowings, maturity	2029
Non-current liabilities, gross	€ 428,500	428,500
Term Loan interest payable
Disclosure of detailed information about borrowings [line items]
Current liabilities	1,315,925	1,833,220
Term Loan interest payable \| EUR
Disclosure of detailed information about borrowings [line items]
Current liabilities	4,272	4,197
Term Loan interest payable \| USD
Disclosure of detailed information about borrowings [line items]
Current liabilities	4,537	10,938
Vendor Loan interest payable \| EUR
Disclosure of detailed information about borrowings [line items]
Current liabilities	1,521	5,487
Senior Notes interest payable \| EUR
Disclosure of detailed information about borrowings [line items]
Non-current liabilities	1,325,221
Current liabilities	€ 3,749	€ 9,373