I hear ya... and as a writer, I've thought about that.... however.....

Yep, there's a chance that you might write something that sounds like something else.... the big question is....

Did the other one become a big hit and make a lot of money or, did your original song that sounds like something else make a lot of money? If the answer is NO.... there's no problem... life goes on.

If the answer is YES.... then the realm of possibilities is pretty wide open. You're likely to meet judges and lawyers and all sorts of folks you would never have met otherwise... but that depends on a few people connected to the original song. Look up the lawsuits of the past. George Harrison with My Sweet Lord, millions changed hands over 3 notes.... but then again, I thought that Lady A's Need you now was a dead ringer copy to Parson's Eye in the Sky, but apparently not.

Heck, it comes down to this.... write your song and don't worry about the fall out that "might" happen.

You can find my music at:
www.herbhartley.com
Add nothing that adds nothing to the music.
You can make excuses or you can make progress but not both.

The magic you are looking for is in the work you are avoiding.