https://dictionary.cambridge.org/grammar/british-grammar/suggest It's explained: Typical errors We don’t use suggest + indirect object + to-infinitive when we suggest an action to someone: He suggested that I should apply for a job in a bank or insurance company. Not: He suggested me to apply … We don’t use suggest + to-infinitive: Henry wanted to tell everyone, but Dora suggested waiting until the news had been announced officially. Not: Dora suggested to wait …

You can use it without "to". For example you can say "I suggest you go home" or "he suggested (that) we work harder". With "to" it's incorrect. I hope that helps.

Nope, it's not correct. The correct form would be: Suggest that you + verb without to I suggest that you take prevents measures. I suggest that she come (without "s") home soon.

What do you mean by "V"?