Following McLaren's update package that was brought forward to Miami, several other teams have stuck to this weekend's Imola Grand Prix to deploy their first major upgrade push of 2024, including Aston and Ferrari.
Aston's Imola spec includes a revamped floor, as well as a new front wing and diffuser as part of what technical director Dan Fallows described as an "aggressive" in-season development programme to make its car better suited to different circuits.
But based on the evidence of Imola qualifying, Stroll doesn't feel like the car upgrades are anywhere near enough to keep pace with the teams ahead.
Stroll went out in Q2 and qualified 13th, three tenths down on Daniel Ricciardo's RB in 10th.
Team-mate Fernando Alonso only managed 19th after his team fought to repair his AMR24 following a crash in FP3, with the Spaniard set to start from the pitlane for the race.
"Just not the day or the weekend we were hoping for with the upgrades we brought, not competitive enough," Stroll said.
"I think everything was working, it's just not good enough, so we keep pushing. Other teams are looking competitive and we are not competitive enough at the moment.
"It feels the same as it felt all year. We brought some upgrades, they might have helped a bit but we need much more to catch those teams further up the grid."
When asked what was missing, he replied: "Downforce, balance, some behavioural stuff that we have been dealing with all year.
"We have to keep bringing upgrades, keep putting downforce on the car and making it quicker, that is the name of the game in Formula 1."
Alonso explained he was fuelled for multiple laps in Q1, so his car was overweight when he set his best lap time at the start of the session.
He then had to pit with an undiagnosed issue, and could not set a faster time towards the end of the session.
"We started with fuel for the whole session, just to give me a little bit of laps and practice. I set the lap time at the very beginning when the car was heavy on fuel," he said.
"And then when the car was light at the end and we put the last set of tyres, I had to box for an unknown problem. It was quite painful.
"I'm sorry for the mechanics because they deserved a little bit better after the job they have done. But yeah, one of those days that everything goes in the wrong place."
