Loans and Borrowings - Schedule of Principal and Interest Payable Outstanding Amounts (Details) - EUR (€) € in Thousands	12 Months Ended
Sep. 30, 2025	Sep. 30, 2024
Disclosure of detailed information about borrowings [line items]
Senior Note embedded derivative	€ 28,638	€ 28,638
Less: amortization under the effective interest method	(24,160)	(23,361)
Non-current liabilities	1,128,010	1,169,965
Current liabilities	€ 17,133	24,670
New Term Loan \| USD
Disclosure of detailed information about borrowings [line items]
Borrowings, maturity	2029
New Term Loan Current \| USD
Disclosure of detailed information about borrowings [line items]
Borrowings, maturity	2026
USD Term Loan \| EUR
Disclosure of detailed information about borrowings [line items]
Borrowings, maturity	2029
Non-current liabilities, gross	€ 375,000	375,000
USD Term Loan \| USD
Disclosure of detailed information about borrowings [line items]
Non-current liabilities, gross	98,641	152,883
Current liabilities	€ 5,090	7,890
Vendor Loan \| EUR
Disclosure of detailed information about borrowings [line items]
Borrowings, maturity	2029
Non-current liabilities, gross	€ 217,408	208,305
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]
Non-current liabilities, gross	1,123,532	1,164,688
Term Loan interest payable \| EUR
Disclosure of detailed information about borrowings [line items]
Current liabilities	2,242	3,591
Term Loan interest payable \| USD
Disclosure of detailed information about borrowings [line items]
Current liabilities	428
Vendor Loan interest payable \| EUR
Disclosure of detailed information about borrowings [line items]
Non-current liabilities, gross	3,983
Current liabilities	0	3,816
Senior Notes interest payable \| EUR
Disclosure of detailed information about borrowings [line items]
Current liabilities	€ 9,373	€ 9,373

Amortization of borrowings.

No definition available.

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- Definition

Long term borrowings, gross.

+ References

No definition available.

+ Details

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- Definition

Senior notes embedded derivative amount.

+ References

No definition available.

+ Details

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- Definition

The maturity of borrowings. [Refer: Borrowings]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IFRS
-Number 7
-IssueDate 2025-01-01
-Paragraph 7
-URI https://taxonomy.ifrs.org/xifrs-link?type=IFRS&num=7&code=ifrs-tx-2025-en-r&anchor=para_7&doctype=Standard
-URIDate 2025-03-27

+ Details

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- Definition

Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with members defined in one or many axes of the table.

+ References

No definition available.

+ Details

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- Definition

The non-current portion of non-current borrowings. [Refer: Borrowings]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Note Expiry date 2027-01-01
-Name IAS
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-IssueDate 2025-01-01
-Paragraph 55
-URI https://taxonomy.ifrs.org/xifrs-link?type=IAS&num=1&code=ifrs-tx-2025-en-b&anchor=para_55&doctype=Standard
-URIDate 2025-03-27

+ Details

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- Definition

The amount of current borrowings. [Refer: Borrowings]

+ References

+ Details

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