I agree with you, Arsenal should avoid wasting time pursuing just one uncertain player, considering that time is more valuable in finding alternatives with comparable talent.
Nicolas Jackson might be a better alternative if they fail to land Gyokeres.
The problem is, Manchester United is also eyeing the Chelsea striker.
If Arsenal were to make an offer to Jackson, I'm sure he'd choose Arsenal over Manchester United.
What makes you believe that Arsenal should focus on Jackson and not Gyøkeres? If the team you support made an offer for Jackson, would you be satisfied with the transfer with his performance for Chelsea for the previous two seasons? Arsenal has a few weeks until the season starts, so they don't need to rush to get a striker. Gyøkeres has chosen Arsenal over any other team, and I'm confident they'll complete the deal.
However, I think you were impressed with Jackson performance for Chelsea, since he scored 24 goals in 65 Premier League appearances, and you believe Arsenal should not just pursue a striker who scored more than 50 goals last season. Jackson may be better than Hojlund, who consistently misses opportunities for Manchester United, but I do not believe making a bid to Jackson would fix their problems. If Manchester United didn't have anyone to sign, Jackson shouldn't be their final option.
If you want to know why I say all that, I'll answer that Arsenal seems to be making it difficult to sign Gyokeres.
I know everyone would be more supportive of Arsenal pursuing Gyokeres. But we have to be realistic: if the terms become more difficult and force Arsenal to spend more money, it would be better to look for other alternatives.
I know Gyokeres is a great player, but judging by his previous experience, he's just starting his big scoring career.
So, there's no guarantee he'll perform the same as he did at Arsenal, as the competition in the Premier League is fierce. Unlike the Portuguese league, this is a different story.