If you have purchased the game on another device, you can extract the IPA using (desktop software).
~4.3 GB (recommend at least 8 GB for installation). Kingdoms DLC: An additional ~7.65 GB. Supported Devices: iPhone: iPhone 8 / 8 Plus and newer. total+war+medieval+2+ipa+upd
Even with the IPA update, performance varies: If you have purchased the game on another