There are a few aspects to this:
Make sure you're developing those "perfectionist" techniques so you can apply them minimally from your usual fighting position - they should snap out with minimal telegraphing. Practice on the heavy bag, making sure you can launch a wide variety of your techniques from the same guard position, as well as advance, retreat, side-step and even jump comfortably. Each should be very direct, minimal and powerful, happening like a click of the fingers rather than with a big windup/backswing or large sluggish movement into the technique. Focus on attacking with that suddenness then returning immediately to the guard or a follow-up technique.
Use the experience/insights into how you can unleash your techniques on the bag to guide how you dynamically maintain a good stance and guard relative to your opponent, so you can unleash your "classic" techniques freely at them.
Make a conscious effort to be flexible and spontaneous mentally in your technique selection, so you're utilising opportunities that arise or you can create and using your "perfectionist" technique in its classic application, rather than fixating on one or a few techniques and trying to make them work when the openings they require aren't available. Constantly during sparring, extend your awareness towards what you can do next that's most likely to be decisive. Take a few risks during friendly practice to help hone your decision-making abilities with feedback. As an example - you might be preparing a powerful reverse punch but see the opponent's going to be able to block it, so throw a front jab to the liver instead.
Which brings us to...
Actually that prevent me from being a creative martial artist, to make a technique in my own way for example, not putting my weight in a strike due to my position in a fight. Another example, I will do a technique like "knee, elbow, punch or even kick" all without putting my body weight in it due to my position.
Should focus on details or should I be creative and do techniques in my own way?
Think over some of the situations where this has happened, and what you might have been able to do if you were "creative". Practice variations of your classic techniques. For example - if you find one opponent always blocks your high section roundhouse/turning/mawashi-geri kicks, you might practice on the bag by introducing a slight delay mid-kick - hopefully they'll tense slightly into a block and you'll actually make contact as they're relaxing again. Or you might withhold the final extension of the kick while turning your kicking leg's knee downwards, then kick downwards at their face. Or bring the knee across without extending the lower leg then hook back in the opposite direction with the heel. Or use some kind of hybrid turning/side kick. Don't think of these things as flawed or poor techniques - practice and explore them with a mindset that a less basic technique that still hits hard enough to do significant damage - or just create an opportunity to do so - is better than a classic technique that's 10 times harder but easily and consistently blocked.
Similarly, a given art might habitually practice a downward "chop", and horizontal chops, but if you realise a diagonally-downwards chop might be a good way to penetrate an opponent's guard, practice such a strike until you're comfortable with it too.
These variations are not necessarily any less "perfect" than your "classic" techniques - you can and should practice them the same with an aim to achieve good speed and optimal power. As you explore such variations, you may start to perceive what I call the "lines of power" around the body - the ways you can coordinate and time the motion of different parts of the body - legs, hips, core muscles, pecs/lats, arms, flexing of the spine etc. to strike powerfully from a wide variety of angles and positions. Your classic techniques are likely prime examples of these lines of power: you want to be so familiar with the classic technique that you can vary say the back foot position then otherwise follow the classic technique and have your attack drive in at the opponent at a correspondingly different angle, all without much compromise to power or speed.
Summarily, you can get a long, long way by sticking to "perfectionist" classic technique if your perfectionist practice has been focused on minimalist, untelegraphed, powerful, snappish movement and you're mentally adjusting your technique selection spontaneously. You get even further by systematically looking back at situations where you've been unable to find an effective technique, and studying variations, strategies or tactics you could try next time. After a while you'll probably manifest spontaneous adaptations too, but I wouldn't try to do that for its own sake - let it happen from a deep foundation of carefully practised techniques. The risk with trying to force creativity is that you create half-baked techniques without sound body-mechanical underpinnings, that may have enough power to block or strike in a friendly dojo situation but will fail you on the street.