Display written sentences with keyanswer after a random number of sound files (wav)

Hi all!
I am new to Psychopy and sort of new to programming too, this is why I tried to create my experiment with the Builder (Psychopy 3.2.4, in Windows 10). I want to do an EEG study which presents audio files that are presented with a fixation cross while the file runs. I am interested in the N400 ERP component and for now we only want a passive listening task. Nevertheless, we want to implement a few attentional checks in every block of the experiment to make sure participants are paying attention and understanding the sequence. There is a first training/practice block with 11 sentences and 3 different testing blocks, each with 45 different wav files. We have 2 conditions: congruent and incongruent, and then the distractors. Every wav file is listed in a .xlsx sheet. In the training block we want to add 3 attentional checks for practising, and 5 attentional checks in each of the 3 blocks. I don’t want them to appear after an exact number of audio files but randomly with at least 1 audio file in between.

My problem is that I don’t really understand how can I add written sentences intermingled with sound files when they are not displayed one after the other in every repetition of the loop. I have thought of saving the written sentences as images (.png) and add them in a new column in the same spreadsheet but I have to add a ‘keyboard’ component to make participants answer ‘yes’ or ‘no’ to that sentence and continue with the following audio stimulus. Moreover, when I run the experiment there is a delay after presenting each wav file, before presenting the following stimulus. I have seen it depends on the computer I run the experiment from, how long the delay is and it is not for all stimuli. Do you know if there is anything I could do to correct it? What I have tried is changing the order of software libraries in the settings, add more time between stimuli to give the system time to load, and substract the delay after seeing it in the log file and manually calculating it.

I attach in the message the experiment I have so far, which works but does not do what I want with one test image I tried to add.
Oras_sentences_def.psyexp (103.6 KB)

The Excelsheet related to is the following:
all_stimuli attCheck.xlsx (14.0 KB)

I would really appreciate your help with this since I feel stuck! I hope I could express myself clearly and sorry if there is anything I did not said correctly.

Thank you in advance.