If you exercised and held ISOs in 2022 your 2023 tax return should have included a Form 8801 to carry the AMT credit forward from your 2022 return. If you didn't use your AMT credit in 2023 it would carry forward to 2024 on Form 8801. You do not enter a "negative bargain element" on your Form 6251 - there is no such thing. What you have is an AMT capital loss. You will need to file an amended 2023 return to include a Form 8801, and then carry that forward to 2024 to use your AMT credit.