Can I omit streusel ingredients for just a black and white swirl pound cake?

I made this pound cake without the streusel two times and they came out great. I would use the timing for the vanilla pound cake (60 to 70 minutes).

Generally, baking is chemistry and changing an element can change the outcome. Sohla El-Wally has strong thoughts and cautions about this, included in some of her recipes and demonstrations.
Given all that, I proceed cautiously.
Maybe look for a plain marble cake recipe written by her or another reputable baker.
Or, if you want to proceed with this one, try it without the streusel but cautiously.
The streusel performs (at least) two functions in this cake.
As it cooks, it browns and the ingredients develop more flavor.
Also, the ingredients give some insulation to the cake batter below them.
Removing the streusel lessens the total volume being baked and removes some of the insulation.
In baking it that way, I would be cautious about over cooking or over-browning if using the same temperature and timing.
Perhaps use the same baking temperature, but check sooner for done-ness. Also, watch the top of the cake and lightly cover it with foil if it seems to be getting dark on top before the inside is fully baked.