So for my birthday, my father got me a new Pokemon card set that you can get at Walmart. The card set he got me was a Venisaur V, but I don't necessarily know what the V means. Is it a better version of GX and EX?
Yes, Pokémon V are the current (Sword and Shield block) two prizer mechanic, which are cards that are very powerful and as a result give the opponent two prizes instead of one when they are knocked out. Pokémon VMAX are even bigger, giving 3 prizes and having more hit points, and evolve from Pokémon V. Pokémon VStar also evolve from Pokémon V, give two prizes, and have a special power (ability or attack) that you can use one total per game (similar to GX attacks). Pokémon V-Union are special Pokémon that require four cards to make, and can be created once per game, and have multiple abilities and attacks typically.
Note, the term "Pokémon V" in most cases refers to Pokémon V, Pokémon VMAX, Pokémon V-Union, and Pokémon VStar, unless it is talking about a specific Pokémon (so "Rayquaza V" is only the V, not the VMax).
When the first full set next year comes out, Pokémon Scarlet and Violet, that will begin a new block with a new mechanic - which is actually an old mechanic; Pokémon ex (not the same as Pokémon EX) - but along the same basic lines. It is a repeat of an older mechanic, and may or may not share the same characteristics.