Reading bl does not mean you're gay and you can enjoy it without it having any effect on your own sexuality/gender identity.
That being said there are plenty of good isekais on this site.
Try a list to start:
https://www.mangago.zone/home/mangalist/2397685/
https://www.mangago.zone/home/mangalist/1799075/
https://www.mangago.zone/home/mangalist/2720625/
https://www.mangago.zone/home/mangalist/477611/
Im not sure whether you are a boy or a girl, but being afraid of BL is valid because of your preference.
I am a gay boy and in the past, I hate straight smut manhwa, but I can bear reading it now because the male are handsome. Im not saying that you should adapt, but it gets better with time.
Then if you dont really want BL......
I have a question?
Did what you read has BL smut? which made you traumatized?
If it is, try to read mild shounen ai BL with no kissing or seggs. I want you to read a mild BL work just to reboot your mind and forget the BL which made you ashamed and then continue reading straight comics after reading one shounen ai.
If you keep denying that you read BL (and if it has a smut) then you will just worry your self more. Instead once again read milder BL forms, then if you dont really like it. Jump to straight or shoujo comics.
dude... this sounds crazy but I asked a stranger about good isekai that it's good to read when you're bored, but he recommend me to read this uhmm... there this two dudes fu**ing each other and im too stunned what i read lol. I'm straight and I just want to spend my time reading good manga, manwha like that... I feel ashamed to myself now, I'm not gay!! I just met this stranger online