I will advise you to contact the sites directly or contribute free content to the sites and request that you include links to your bio that redirect people to your site.
Also, you could consider including the links within the body of the post.
Avoid the free backlinks site. They can mess things up for your site.
Any link exchange can or could cause either a positive or negative effect which will already effect rankings before noticing and won't revert to exact positioning by just deleting. So you can miss out on power on links that may benefit dead domains as you read the one negative point and think better not even attempt. People register domains that have had previous problems they sort them out and it isn't end of world.