to link portals properly from overworld->nether, divde the overworld portals x and z coordinates by 8 and round it to the nearest whole number, then build the portal in the nether there. This should work
On Bedrock portals don't work like in Java, try going in the new portal and then exiting. Doing some combinations like these sometimes fixes the glitch. Did you move the portal in Nether? Did you move it by the X and Z coordinates (left, right, forward, back) or did you just move it by the Y coordinate (up and down)? Maybe it's because you deleted the old portal. Try destroying the one in Nether and the extra one in the Overworld. When you destroy the one in Nether you need to stay there and then type */kill @s* . After you've done that try entering the big portal again. See where it takes you. In Nether, you need to move your portal up or down, not left or right. If this didn't help try searching how to link portals on Bedrock
to link portals properly from overworld->nether, divde the overworld portals x and z coordinates by 8 and round it to the nearest whole number, then build the portal in the nether there. This should work
On Bedrock portals don't work like in Java, try going in the new portal and then exiting. Doing some combinations like these sometimes fixes the glitch. Did you move the portal in Nether? Did you move it by the X and Z coordinates (left, right, forward, back) or did you just move it by the Y coordinate (up and down)? Maybe it's because you deleted the old portal. Try destroying the one in Nether and the extra one in the Overworld. When you destroy the one in Nether you need to stay there and then type */kill @s* . After you've done that try entering the big portal again. See where it takes you. In Nether, you need to move your portal up or down, not left or right.
If this didn't help try searching how to link portals on Bedrock