If your website is identified as having a very low-quality backlink profile, Google will issue a penalty. These penalties may be manual or algorithmic, but both affect your website in the same way.
Google Penalty can prevent your website from ranking high on search engine results. A Google penalty may prevent you from indexing your website in more severe cases, so appealing to ASAP be a must

Make sure you do not buy backlinks on your website instead of creating your high-quality links to avoid getting a Google penalty. It is also essential to maintain your backlink profile by regularly auditing so that malicious links can be removed before it is too late.

If your keyword ranking is on Google, do not look for positive changes overnight. The more effort and time need to fix the problem and wait for another algorithm update. You will notice that core updates usually occur twice a year, anywhere from 6-8 months. This is a good ballpark number to remember if you take proper care to solve problems. You are expected to invest up to 100-hours in solving the issues that initially caused the problem.