E-Mail not working after IOS 18 updates

I know this issue has been going on for some time. I've just updated to IOS 18.3.2 and my I-phone and I-pad and watch are not receiving emails immediately. They come in sometimes many hours later in dribs and drabs. This also applies to my husband's phone and Ipad. I thought this issue would have been solved by now so can anyone advise when this bug will be fixed. Ive tried ALL the fixes people have suggested to no avail. Thank you for any help.