I agree with one space.
Although you can use two spaces, one space is considered ‘correct.’ About 25 years ago in typing class, I was taught to put two spaces after a period. It’s been very difficult to break that habit.
Using two spaces was a temporary American practice. On a typewriter, every letter occupied the same space, so using two spaces after a period supposedly increased legibility. Computers have proportional spacing, so the width of any letter (or punctuation mark) varies, which makes legibility much easier.
Most (if not all) major style manuals (MLA, APA) specify using only one space after a period.
There are many reasons for using only one space.
There was never proof that inserting an extra space improved readability.
Publications in print use only space, so if you ever submit your work to a publisher, they will request using only one space.
Using an extra keystroke for every sentence is not very efficient.