When it comes to iMessage history, if the messages were in iCloud and you deleted the old device from your iCloud account, the messages should still be available on your current device, assuming they were fully synced before the removal.
However, if the messages were stored only on the old device and not synced with iCloud, you may need access to the old device to recover them. Here are a couple of options:
1. If you have a backup of your old device (either on iCloud or iTunes) from a time when the messages were still present, you could restore this backup onto a different iOS device (not your current one as this would overwrite your current data).
2. If the person who has your old phone hasn’t overwritten or deleted the messages, you may be able to recover them by logging into your old Apple ID on that phone. However, this could potentially cause data loss for the current user of the device, so you would need to make sure they have a backup and are okay with this process.
Remember that manipulating someone else’s device should only be done with their full understanding and consent. If neither of these options work, unfortunately, it might be the case that the messages are irretrievable.
It’s always a good idea to regularly back up your device to prevent such situations in the future.