Goodness, you've asked a question which really has no answer. How about this one: "it depends".
Goals are pretty rarely scored in isolation, it's usually a team effort, and the best scorer for YOUR squad depends on what your side can produce to set up that scorer. If you have some great crossers out on the wing, maybe you want a player who can finish those. Maybe you have trouble creating anything, and a free kick specialist would be the best way to add goals to your side. Perhaps you have a great corner taker, and someone who can get in to head those home would be your biggest boon (I know one year in one career a few FM seasons ago I had a case where a centreback was very close to the team's top scorer, entirely due to this effect). Perhaps your squad has trouble creating situations and you need someone who has the ability to make goals from individual efforts. What if you do best at counter attacks, and you need to look for someone who can release, outrun everyone to a long ball, and then beat the keeper 1v1? Or, you may end up with a team where the scoring ends up evenly distributed, there really isn't a "great goalscorer", as long as you have enough players to take advantage of what /is/ made available.
I say these because I've had successes with all these models, and sometimes several different ones over a run of years with the same side. I had a long run with a Newcastle side which for a while didn't have a classical goal scorer and relied on set pieces, "garbage" goals from poachers, a set of young strikers with promise who might contribute goals in bunches, but rarely on a consistent basis, etc; then after some years of success (and a growing warchest) brought in C.Ronaldo, who was a very good player, but only when moved to mostly forward did he become a huge goalscorer. When he stated to get old, a no longer young Sergio Aguero was brought in as a gradual changeover, and he became a huge scorer too.
And in terms of recommending any specific person beyond this guideline of "look what fits best with your side", the player attributes are randomized at each career startup, so who might be a monster in one game might not be in another.
FM is a little unlike real life, in my opinion it relies a bit too much on the definition of "position". It's hard to call Messi a "striker", though in today's world football he's an amazing scorer obviously. Since you would tend to play him at a position that's more midfield than forward, he just never seems to score as much in FM (for me, I'm sure others have had different answers). Ronaldo is the other great world scorer, who also isn't classically a forward. Real life football at the highest levels involves a lot more fluidity than FM can account for, e.g. if you pick a formation where you have three forward-type players but you've put two in wing positions, FM penalises you too much because they are better at forward than at AM R/L according to the ratings. Anyway...
Understand your side, and go do searches on the important attributes, which will be things like finishing, composure, dribbling, heading, off the ball, pace, etc. depending on what you think your team can accomplish.